Unprofessional service

I app**** for a top up sim and upon receiving it I realized that it was not conducive for my my needs so I called FNB and canceled it and explained to 3 agents that I spoke to that I want to revert to my old SIM card as I’m using my phone for work purposes, the 1st agent said it takes 24 hours and that was two weeks back. Till today I can’t use my SIM card, the FNB sim is still not canceled, I am unable to perform my duties and my work is dismally affected, I want FNB to cancel their SIM card with immediate effect